There is a need to destroy, or reclaim, explosive materials as part of the demilitarization effort. Procedures conventionally used to demilitarize conventional munitions include incineration of reclaimed explosives and open burning or detonation. Some explosive materials, such as ammonium picrate, also known as Explosive "D", are of high enough purity to be economically suitable for conversion to higher value chemicals.
The destruction of nitrogen-containing explosives has been the subject of various disclosures. For example, German patent publication DE 413 147-A1 discloses the hydrogenation of nitro-aromatic explosives in the presence of an alcohol solvent, hydrogen, and a catalyst at a temperature of about 40.degree. C. to 100.degree. C. Also, U.S. Pat. No. 4,661,179 discloses a process for destroying waste explosives containing nitro, nitrate, or nitroamino groups by hydrogenation. Further, U.S. Pat. No. 5,582,119 teaches a method for destroying explosive waste, such as those containing ammonium picrate, by use of a vessel containing a hot granular bed of sand to ignite the waste and to dampen explosive forces generated by its ignition.
U.S. Pat. No. 5,530,175 discloses a process for converting ammonium picrate to oxygenated products, particularly hydroquinone or cyclohexanediol and ammonia, by hydrogenation over a supported Group VIII metal catalyst. The ammonium picrate is dissolved in a suitable solvent, then hydrogenated at a temperature of about 25.degree. to 250.degree. C., followed by separation of the resulting products and ammonia.
It is also known in the art that ammonium picrate can be converted to picric acid by acidification with a strong acid, at an appropriate pH and acid/salt ratio in an aqueous system. The concentration of picric acid must be kept relatively low because as the concentration of picric acid increases, its rate of formation decreases.
While there exists methods for converting ammonium picrate to more useful products, such as to picric acid, there remains a need for processes that can do this conversion more efficiently and economically.